Virginia Gov. Charles S. Robb said today that he had urged Democrat Walter F. Mondale to personally avoid making religion and politics an issue in his campaign against President Reagan.

Robb, who met with Mondale and other Democratic governors in Minnesota recently, said at a press conference here today that he had told Mondale to "leave it to other established religious organizations" to question the influence of fundamentalist church leaders in the Republican Party.

"I suggested . . . he Mondale not become involved," Robb said.

Robb declined, however, to question the Democratic presidential nominee for attacking Reagan for injecting religion into the campaign in an effort to win fundamentalist Christian votes.

"I'm not suggesting Mondale's criticism is inappropriate," said Robb. The governor spent several minutes at the news conference explaining his position and disputing a Time magazine item that said he had urged Monday to raise the issue of Reagan's affinities for the religious right. Robb said if Mondale's current plan is to keep the issue of religion from becoming a campaign issue "he's following sound advice."

Robb, who was mentioned briefly in a long Time story on the issue of religion and politics, also disputed remarks attributed to him that the Rev. Jerry Falwell, head of the Virginia-based Moral Majority, is the "the most unpopular person in the state."

Robb acknowledged that he raised the question of Falwell's popularity in the private meeting, but said the basis of the quote came a book by Larry Sabeto, a University of Virginia political scientist who has studied Virginia politics for 10 years.

Robb also declined to comment today on a United Press International interview of Donald Huffman, chairman of the Virginia Republican Party. He was quoted in Roanoke as saying that liberal political thought in this country is moving "away from God."

Huffman, who was unavailable for comment, told the UPI that evangelical Christians are becoming more politically active and have generally embraced the conservative philosophy of the Republican Party, especially on such issues as prayer in public schools.

Huffman, a member of the fundamentalist Shenandoah Baptist Church in Roanoke, told the UPI that he was not suggesting all liberals were godless or that religion was a major issue in the presidential race.

"The thrust of liberal thought and the liberal political movement today is away from God while the thrust of conservative thought and the conservative political movement is toward a belief in God," Huffman told UPI.